Summary of Work: This project is designed to determine the relationships among DNA repair, chromosome structure, and mutagenesis in Drosophila melanogaster. Mutations that increase the mutant frequency (mutators) have been identified in the mu2 gene and characterized. These mutations appear to disrupt chromatin structure in the oocyte, but not the sperm chromosomes, so that oocyte chromosomes are not repaired properly, and instead are capped with a new telomere. Given that mu2 mutations also increase mitotic recombination, it is reasonable to expect that the MU2 protein also associates with somatic chromosomes. Antibodies have been made to the MU2 protein and will be used to ascertain intracellular localization. We also plan to look for other gene products that might interact with MU2 using the yeast two- hybrid system. Double mutants will also be made using mutations for mu2 and mutations for either HP1, a putative capping protein, and Ku70. - Chromatin, DNA Damage, DNA Repair, Drosophila Melanogaster, Heterochromatin, Oocyte, Telomere